1. Field of Invention
Hooded cartons, cartons with means for locking the cover in place after the seal has once been broken, carton blanks for production thereof, and locking carton end closures.
2. Prior Art
The prior art is replete with numerous so-called "flip top" cartons having a cover hingedly connected to the top edge of the rear wall, including such cartons as provide locking means for locking the cover thereof in place after the seal has once been broken. Some representative cartons of this type are illustratively disclosed in U.S. Pat. Nos. 3,191,848, 3,378,188, 3,893,614, and Reissue 26,471. Additional cartons of this type are disclosed in U.S. Pat. Nos. 3,294,309 and 3,295,742. Although numerous carton structures of this general type have been proposed, most of them in practice leave much to be desired and suffer from various disadvantages and shortcomings.
One particular shortcoming of previous reclosable hooded lock cartons is that certain of them have depended for positive relocking upon exact squaring up of the carton during its erection, with the resultant effect that, when the carton was not perfectly square, the efficiency of the lock means was impaired considerably. Another shortcoming of previous lock carton constructions has been that the lock flaps frequently substantially abutted each other only along a single horizontal cut or perforation line, as said cut or perforation line existed in the erected and opened and then reclosed carton, so that even when the lock flaps were in substantially abutting mutual engagement with each other, the area or linear distance of said substantial abutment was less than desired. Both of these shortcomings are obviated by the present invention, in which the positive locking effect of the lock members according to the invention is not dependent upon perfect squaring of the carton upon erection and in which the one lock flap, separated from the other lock flap by a peripheral cut, actually has surrounding edges for substantial abutting mutual engagement with the first said lock flap along its entire periphery, except of course on an edge thereof which is articulated to the upper edge of the carton front wall.
Another shortcoming of prior art cartons, wherein the two lock flaps were severed from each other along a line of severance during original opening of the package, has been that, when the rupture along the line of severance has been other than precise, the abutting mutual engagement resulting upon reclosure of the carton has been less than desirable, frequently resulting in a skewed relationship between the cover and carton body upon reclosure, or even an impossibility of locking upon reclosure in the event that actual severance substantially departed from the intended line of severance between the two lock elements. This objection is essentially avoided in the lock means and cartons of the present invention, since the two lock elements are not ruptured from each other upon original opening of the package and do not depend upon abutting mutual engagement along a line of severance, much less a substantially horizontal line of severance, but rather depend for their substantially abutting mutual engagement upon the peripheral or circumferential abutting mutual engagement of the two lock elements along all of the free edges of the lock flap which is articulated to the upper edge of the carton front face panel, except of course that portion of the said lock flap which is articulated to the upper edge of the said carton front face panel.
The carton structure, and particularly the carton lock structure, of the present invention thus have a number of advantages over similar cartons and similar lock structures of the prior art. The carton is of course of the "flip-top" type and is hooded, that is, has side panels which slide over the mouth of the carton and provide an efficient and safe enclosure for the carton end. The carton is provided with lock flaps for retaining the cover in closed position, even after the main seal of the carton has been originally broken. Moreover, the lock flaps of the particular structure of the invention are so formed that their engaging edges are completely unattached to each other, thus permitting smooth complementary and surrounding engaging surfaces, as opposed to prior art compounds which utilize lock flaps which are detachably connected to each other at a severance line and which serve for retaining the cover in sealed position. The edges of such lock flaps are unfortunately jagged and irregular and hinder and even adversely affect the proper operation of the lock flap or flaps. Moreover, some of the cartons of the prior art require engagement of lock flaps attached to the upper edge of a carton front panel beneath cutaway carton side wall end flaps, similar to the glue flaps in the cover of the present invention, alone or in addition to engagement with a centrally-located complementary member on the inside surface of the cover front panel. Unfortunately, this has the further complication that the substantially abutting mutual engagement desired between the carton cover side wall end flaps and lock flaps attached to the upper edge of the carton front panel is seriously affected when these end flaps attached to the cover front panel interior surface are not in complete alignment, as often occurs when a carton is not completely squared up or a cover is not completely squared up during carton formation and sealing. Moreover, in numerous reclosable cartons of the prior art, it is necessary that cutaway or breakaway side panels be provided for adequate original closure and reclosure, and that the reclosure be effected by lock means between cover side panels and carton side panels as well as between cover front panel and carton front panel. Although such structures are indeed operative, they are undesirably complex and additionally require the employment of substantial additional quantities of paperboard for their construction, thereby seriously impairing their favorable economics. The carton of the present invention and the lock means of the present invention are relatively inexpensive to produce, simple to construct, fill, and seal, and they do not require a redesign of machinery for assembly. The cartons of the present invention have a positive lock due to the clean-cut edges of the opposing complementary lock members. A better solution to the problem of reclosable hooded cartons is long overdue, and one such better solution is provided by the carton, carton lock means, and carton end closure of the present invention.